1. Field of the Invention
The present invention relates to a limiter device intended to equip an agricultural machine comprising a first assembly intended to be connected to a first unit and a second assembly intended to be connected to a second unit, said second unit being connected to said first unit by means of an articulation allowing said second unit to pivot about the axis of said articulation within the limits allowed by at least one stop forming part of said limiter device.
2. Discussion of the Background
Document FR-A-2 726 152 discloses an agricultural machine intended for cutting plant matter equipped with such a limiter device. This agricultural machine, broadly speaking, comprises:
a hitching structure intended to be connected to a motor vehicle; PA1 a cutting mechanism, intended to be driven in motion by the motor vehicle by means of drive members and which may extend: PA1 a suspension arm connected, on the one hand, to the hitching structure and, on the other hand, to the middle of the cutting mechanism by means of an articulation of longitudinal axis oriented in the direction of forward travel during work when said cutting mechanism is in the working position, so as to allow this mechanism to pivot about said longitudinal axis; and PA1 a limiter device intended, on the one hand, to limit the pivoting of said cutting mechanism when the latter is in the working position or windrowing position and, on the other hand, to prevent said pivoting when said cutting mechanism is in the transport position. This known limiter device comprises a first assembly connected to the suspension arm and a second assembly connected to the cutting mechanism. The first assembly comprises a catch which can pivot about an axis of pivoting and is intended to interact with two stops belonging to a limiter which forms part of the second assembly. The limiter for this purpose comprises an elongate opening inside which the axis about which the catch can pivot extends, the ends of said opening each forming a stop. PA1 a hitching structure intended to be connected to a motor vehicle; PA1 a cutting mechanism extending: PA1 a suspension arm connected, on the one hand, to the hitching structure and, on the other hand, to the cutting mechanism by means of an articulation whose axis is oriented at least substantially in the direction of forward travel during work when said cutting mechanism is in the working position, so as to allow said cutting mechanism to pivot about said axis; PA1 a limiter device comprising at least one stop allowing said cutting mechanism to pivot about said axis within the limits allowed by the stop(s), the suspension arm forming the first unit, and the cutting mechanism forming the second unit. PA1 the second pivoting torque is greater than the first pivoting torque; PA1 the stop(s) comprises (comprise) at least one elastic element connected to one of the assemblies and intended to come into contact with the other assembly when the second unit pivots about the axis by a certain amount, this (these) elastic element(s) in particular allows (allow) the second unit to widely pivot about the axis of the articulation connecting this unit to the first unit; PA1 the second unit can pivot about the axis in two distinct phases: PA1 the elastic element(s) is (are) intended to return the second unit from the second phase to the first phase, which in particular makes it possible to ensure that the second unit is in a certain position when it is no longer subjected to a pivoting torque or a relatively low pivoting torque; PA1 the position and/or stiffness of the stop(s) is (are) adjustable so as to allow the position of the second unit when no longer subjected to a pivoting torque or to a very small pivoting torque to be adjusted, on the one hand, and so as to allow the intensity of the pivoting torque that will allow said second unit to be pivoted further about the axis of the articulation to be adjusted, on the other hand; PA1 the stop(s) is (are) intended to dissipate all or some of the forces generated by the pivoting of the second unit about the axis of the articulation; PA1 the limiter device is combined with a locking device intended to at least substantially prevent the pivoting of the second unit about the axis of the articulation; PA1 the locking device comprises a catch connected to one of the assemblies and intended to act on the other assembly in order to prevent the second unit from pivoting about the axis of the articulation; PA1 an operating device intended to operate the locking device is provided; PA1 the cutting mechanism may be pivoted into a transport position, when brought into the transport position, the operating device automatically operates the locking device, which automatically prevents the cutting mechanism from pivoting when brought into said transport position.
in the working position, transversely to the direction of forward travel and resting on the ground; PA2 in the windrowing position, transversely to the direction of forward travel and above the surface of the ground; and PA2 in a transport position. PA2 in the working position, transversely to the direction of forward travel and resting on the ground; PA2 in the windrowing position, transversely to the direction of forward travel and above the surface of the ground; PA2 a first phase, to which the limited pivoting of said second unit corresponds and in which said second unit pivots freely about said axis between the limits allowed by the stop(s); PA2 a second phase to which the much greater pivoting of said second unit corresponds and in which said second unit pivots about said axis between the limits allowed by the stop(s) against the forces developed by the elastic element(s);
In the working position and in the windrowing position, the catch is retracted so as to allow the limiter, more specifically the elongate opening, to move with respect to the axis about which said catch can pivot, and to do so within the limits allowed by the ends of said opening, thus allowing the cutting mechanism to pivot about the articulation which connects it to the suspension arm.
In the transport position, the catch is pivoted about its axis of pivoting so that it extends substantially parallel to the elongate opening of the limiter so as to come into contact, on the one hand, with one of the ends of said opening and, on the other end, with the other end of said opening. Such a construction practically prevents any movement by the elongate opening with respect to said axis of pivoting and therefore prevent the cutting mechanism from pivoting about the articulation that connects it to the suspension arm.
The cutting mechanism comprises cutting members located in a line that is transverse to the direction of forward travel, which members are intended to be driven in rotation by the drive members.
For this, the drive members comprise a telescopic transmission shaft with universal joints, which extends transversely to the direction of forward travel when the cutting mechanism is in the working position. This transmission shaft is intended to transmit the movement to a transmission gearbox situated above the cutting member closest to the hitching structure.
One of the advantages of this known limiter device is that it allows, especially in the working position, a large and free pivoting of the cutting mechanism about the articulation that connects it to the suspension arm. Such a pivoting of the cutting mechanism allows the latter to closely follow the lie of the land during work.
It is, however, commonplace during work, for cut plant matter or earth to stick to the cutting mechanism, and this has the effect of weighing down and unbalancing said cutting mechanism when the latter is extended in the windrowing position. Because of this, the cutting mechanism pivots to one side or the other about the longitudinal axis of the articulation connecting it to the suspension arm, and the result of this is to reduce the ground clearance of said known agricultural machine. There is a risk that such an agricultural machine will, in the windrowing position, extend too close to the ground and thereby hamper maneuvers at the end of the field which will require the operator to be more attentive during maneuvers at the end of the field and all too often result in a collision between the cutting mechanism and the ground. There is the risk that such collisions between the cutting mechanism and the ground may damage the agricultural machine.